Rail wagon brake beam is the most important part in a basic brake device for rail wagons. When a vehicle brakes, the brake beam can transfer the brake force generated by a brake cylinder to brake shoes, so as to achieve braking of the vehicle. FIG. 1 is a schematic structure diagram of a brake beam. The brake beam 6 is a triangle-like beam, including a cross rod 61 in the horizontal direction and diagonal rods 62 provided at two end portions of the cross rod 61; the diagonal rods 62 are inclined downward to be intersected at one point; a beam strut 63 is uprightly provided between the point and the cross rod 61; and when in normal use, the brake beam 6 is horizontally arranged.
To ensure the application reliability of the brake beam, a fatigue test is to be performed on the brake beam. When a fatigue test is performed on the brake beam, two ends of the cross rod 61 of the brake beam respectively pass through two mounting holes in the middle of two brake shoe holders and are respectively mounted on the brake shoe holders. A simulated brake shoe is mounted on a simulated wheel pair by a brake shoe holder, and the coordination between the simulated brake shoe and a simulated wheel tread should be in accordance with the actual conditions. The mounting between the simulated brake shoe and the brake shoe holder and the mounting between the simulated brake shoe and the simulated wheels are firm, so as to ensure that there is no sliding during the loading process. The simulated wheel should have a degree of freedom for rotating around the axis thereof and a degree of linear displacement freedom for restricting an end of the brake beam moving along the tangential direction of the wheel treading surface. After the brake beam is properly mounted, a pressure load and a tangential load are simultaneously applied to the brake beam, wherein the pressure load acts on a beam strut pin hole, varying from 0 kN to 104.5 kN; and the tangential load produces between the simulated wheel tread and the two simulated brake shoes, varying from −43.7 kN to 43.7 kN.
At present, there are three types of brake beam fatigue test stands. The first type is characterized by mounting brake beams in the transverse direction. With regard to this type, although the direction in which the brake beam is placed on the test stand is consistent with that during the practical application, the fatigue test can be performed on only one brake beam each time, thus having a low test efficiency. The second type is characterized by placing the brake beam in the transverse direction. With regard to the second type, two brake beams can be simultaneously tested, and a pressure load is applied by a transverse actuator and a tangential load is applied by a vertical actuator. However, a test stand of this type occupies a large space, and a load is to be applied respectively in transverse and vertical directions. In this way, the test stand has a complicated structure, and since it is unable to replace simulated wheels of different wheel diameters, the test stand cannot be adapted to brake beams of different types. The third type is a gantry-type test stand. With regard to the third type, brake beams are placed in a vertical direction, and two brake beams can be simultaneously tested; and both the pressure load and the tangential load are applied by a vertical actuator. The whole structure of a test stand of this type has a relatively low stiffness, and a relatively high deformation will thus occur during the loading process in the fatigue test, and consequently, the improvement to the test loading frequency and test efficiency is influenced. At present, the maximum test loading frequency is 2.3 HZ. The gantry of the test stand has a low strength, and fatigue cracks are likely to occur on the gantry structure body. There are too many gaps in the connection portion between the test stand and the brake beam to be tested, and it is difficult to adjust those gaps.